Control system for fluid fuel burners



Sept. 16, 1952 WEBER CQNTROL SYSTEM FOR FLUID FUEL BURNERS Filed Nov.15. 1950 INVENTOR. Vwop Meben BY ms m Patented Sept. 16, 1952 TIQNTROLSYSTEM FOR FLUIDFUEL BURNERS tVictor Weber, Greensburg, Pa., assignoreto Robertshaw-Fulton Controls Company, Greensbnrg Pa v acotporation. ,ofDelaware 1 .Application'November 15, 1950, Serial No.2I-95;765

I'll-Claims.

C1 The invention "relates to control systems for. fluid fuel'burners'and mor rpar-ticularly to electrically operable appa'ratus of; thistype.

Infl'u-id fuel'burning'apparatus, itvis often de- .sirableto=fiectautomatic operation of the burners bvmeans ofatirriingrmechanism. To this :end; it isanobj ect of this inventionto'control the admissionvoFfu'el: to theburners in timed intervent theescape-of unburned-"fuel from-the burnersin therevent-of a powerfailure. I A='preferred ei'nbo'dir'nent o'f-the present inventiencomprises amain burnersupplied with fuel by w conduit, the flbw'ofifuelin whichfis' under thecontrolof a=normally closed valve movable toanopen position by a 'd'e'vice responsive to the presence o'f'flame:at'the pilot burner. Fuel flow to thenorma'elly closed valv andto the pilot burner is controlle'd bya manually operable'valve, thesupply of fuel td which isin turn 'controlledbyan.electrica1ly-:.operab1e valve.

:An .energizing:circuit for the actuating: means oftheselectricali-ytoperablewalve includes a pair of switches invseries'.'l'lhefirst of the pair is operativelyiaconnected'itdaaclock mechanism.to be openedsand:closed1therebyxand the second switch of theatpairsis.operatively :associated with the manuallyaoperableuvalveito:be. openedwhen the valve-tie :.close:d sand :close'd. zwhen the :valve J isopened.

efelectric igniter is provided for the" pilot burners-and has anenergizing circuit connected inzparazllelz'with thetactuating means ofthe electrically operablevvalve. eThe' igniter energizingcircuittincludes-sa switch operatively associatedwithzactuatingrmeansiresponsive to the presence ofza flameiatither pilotburner to be'opened in the presence of.-such:flame.and closed in theabsence thereof.

:Further.Lobiectsiandladvantages will be apparent :from the:accompanying specification 1 and claims taken'zwithxthe drawing whichis a schematicwview of a control-system for a fuel burner ing shown insection.

"Referring to: the drawing, the control system is shown as associatedwith a main burner I16 whichireceivesp/fuelfrom a supply conduit l2,flow of fueliromzthe supply:conduit l2 to the main burnerlllubeingunderthecontrol'of thermally responsiveivalve. means M, manually operablevalve .means. 1 l6, and electrically .openable valve meansgheretshowmasasolenoidivalve 1:8.

. Anlelectric.igniter12fl'cisnisposed in. ignitingzreiation withiapilotburner' 22. inturn disposed in igniting relation:.with1the mainburnerle. 1..Ihe pilot burner; 22. is: supplied with fuelrbyxa. conduit24hconnected therewith, flow ..of;:fuel inrthe -conduit;24. beingcontrolleduby theimanually operable valvelmeans 1 I6. I

A :casing' 2 6 ."may contain the thermally responsive valvemeans H'WhiChmay comprise valve chamber 28 formed in the casing 26 and providedwithan inlet opening 30 andLan outlet openingi32. The:outlet..openingiflcommunicates with a pipe 34 connected toithemain burner I0. Disposediinthe valveichamber 28..isa valve seat 36. cooperable withavalveslelement' 38' to :interruptjflow between the inlet; 3:0andithesoutlet132. A coil spring 40 acts.betweenrawallifl :of'the-valvechamber 28 and the valvamember 38 to bias the valve member 38intoengagement*withthe valve-seat 36. Depending from the lower side ofthe valve m-emberi38:iszva valve stem 44 which' extends through a bore46" in the casing 26. The diameter ofthe, bore46 iszsufiicient to'permit axial-movementofrthevalve stem44-therein. The'free end 48 ofzthevalvelst'em 44 extends beneath the casing .26- tosabutra lever 50whichis pivoted at one-end 52in. a'; bracket: 51 securednto the casing26.

Theulever 50 is adapted to be moved about its pivotbytiathermally-responsive device which may comprisethe usualexpansibleelement 56, capillary.tube;58, and bulb 60. .The bulb isdisposedadjacent 'thekpilot burneri'lz'to beheatedbya flame emanating therefrom.Theeexpansible element 56 ismounted. ona'cover62 securedinfiuid sealing?relationsto the. lowerlsideofithe casingLZB byiany suitablemeans(notshown). Movement isltransmitted fromthe:expansible -element. 56- tothelever 5flfibyimeans of a thrust button 64lcarried on the vuppersurface .of. the expansible element 56. It willbe apparentithat intheabsence ofa flame at thepilotlburnerfi the expansiblevelement" 56 willbe inits contracted condition and I the spring 148 will hold the valvemember 38 against the valve seat 36. Itiwill also .be'apparent that aflame emanatingfrom the pilotuburner 22-wil1-be efiective'tojheatthebulb 60 to' cause expansion of the e-xpansible'element 56,counterclockwise rotation of the lever 50 and movement 3 of the valvemember 38 against the bias of the spring 40 and away from the valve seat36.

The manually operable means I 6 may comprise a simple fuel cock (notshown) mounted in a casing 66 for rotation between fuel flow permittingand fuel flow preventing positions. Manual rotation of the cock may beeffected by means of a knob 68 connected to the cock through a stem 10.

Fuel may be admitted to the casing 66 of the manually operable valvemeans I6 through a conduit I2 connected therewith and egress of fuelfrom the casing 66 may be had through a pair of outlets. One of the pairof outlets communicates with a conduit I4 which communicates with theinlet 30 of the valve chamber 28 of the thermally responsive valve meansI4. The other of the pair of outlets communicates with the conduit 24connected to the pilot burner 22. The manually operable valve means I6thus controls the flow of fuel to both the thermally responsive valve I4and pilot burner 22.

Flow of fuel to the thermally responsive valve means I4 may also beunder the control of condition responsive valve means which may comprisea thermostatically controlled valve combined with the manually operablevalve means in a manner well known in the art. The thermostatic controlfor the thermostatically controlled valve may include a temperaturesensing element here shown as a bulb I6 exposed to the temperature ofthe space to be heated by the main burner I and connected to a valveactuating mechanism (not shown) by a capillary tube '18. Since combinedfuel cocks and thermostatically controlled valves are well known in theart, further description is believed to be unnecessary.

The solenoid valve I6 is normally closed and is adapted to be openedwhen the solenoid winding thereof is energized. The solenoid valve I8 isconnected to a conduit 80 in communication with the supply conduit I2and also to the conduit I2 which communicates with the casing 66 of themanually operable valve means I6. Thus, the solenoid valve I8 controlsthe flow of fuel to the manually operable valve means I6.

A stand-by pilot burner 82 is disposed in igniting relation with themain burner I0 and is connected to the supply conduit I2 by conduits 84and 86. Flow of fuel to the stand-by pilot burner 82 is under thecontrol of valve means 88 which may comprise a valve chamber 90 formedin the casing 26 and provided with an inlet 92 and an outlet 94. Theinlet opening 92 communicates with the conduit 86 and the outlet opening94 communicates with the conduit 84. A valve seat 98 disposed in thevalve chamber 90 is cooperable with a valve member 98 to interrupt flowbetween the inlet opening 92 and the outlet opening 94.

A valve stem I00 is slidably carried in a bore I 02 formed in the casing26 and extends between the valve member 98 and a lever 50 of thethermally responsive actuating means. It will be apparent that rotationof the lever 50 under the influence of a flame at the pilot burner 22will cause an upward movement of the valve stem I00 and associated valvemember 98 to move the valve member 98 away from the valve seat 96. Whenthe valve member 98 is not so moved it will be held against the valveseat 96 by the pressure of the fuel supply acting thereon.

A standby pilot control of the type herein disclosed is disclosed andclaimed in the copend- 4 ing application of Charles K. Strobel, SerialNo. 189,584, filed October 11, 1950.

Also disposed within the casing 26 is a thermally responsive switchingdevice I04. Secured to the bottom of a recess I06 formed in the casing26 is an apertured element I08 formed of suitable insulating materialand carrying thereon a pair of contacts III). The contacts IIO arearranged in spaced relation and are engageable by a movable plate II2 tocomplete a circuit therebetween. A coil spring II4 acts between themovable plate H2 and a closure member I I6 to bias the plate II 2 intoengagement with the contacts IIO.

An operative connection is established between the movable plate II2 ofthe switching device I04 and the lever 50 of the thermally responsiveactuating device by a push rod II 8 slidably carried in a bore I20formed in the casing 26. The push rod II8 extends through the aperturedelement I08 to engage the movable plate I I0 and also extends beneaththe casing 26 to abut the lever 50. It will be apparent that when theexpansible element 56 is in its nonexpanded condition, the coil springH4 of the switching device I 04 will maintain the plate I I2 inengagement with the contacts H0 and that counterclockwise rotation ofthe lever 50 about its pivot 52, upon expansion of the expansibleelement 56, will cause upward movement of the push rod H8 and the plateII2 associated therewith to disengage the plate H2 and the contacts IIO.

Movement of the solenoid valve between fuel flow permitting and fuelflow preventing positions is under the control of a timing mechanismsindicated generally by the reference numeral I22. This mechanismincludes switch means having a switch blade I24 pivoted at I26 to bemovable into and out of engagement with a fixed contact I28. The switchblade I24 is connected to a reciprocal plunger I30 of a timer I32. Theclock timer I32 may be of any suitable form and may be manually adjustedto cause axial movement of the plunger I30 at preselected times. It isunderstood that the timer I32 may also be manually adjusted to set andretain the plunger I38 in its retracted or extended position. As timingdevices of this type are well known in the art, further description ofthe timer I32 is deemed unnecessary.

The switch I24--I28 of the clock actuated mechanism I22 forms a part ofan energizing circuit for the solenoid of the solenoid valve I8 andserves to connect the solenoid winding of the solenoid valve I8 to asource of commercial current here shown as line wires LI and L2 as willmore fully appear. Thus, movement of the solenoid valve between fuelflow permitting and fuel flow preventing positions is under the controlof the timing mechanism I 22.

Movement of the solenoid valve I8 is also under the control of a switchI32 operatively associated with the manually operable valve means I6.The switch I32 also forms a part of the energizing circuit of thesolenoid valve I8 and is here shown as including an actuating lever I34engageable by a cam element I36 carried by the stem 10 of the manuallyoperable valve means I6 to be rotatable therewith. The switch I32 is sodesigned that rotation of the knob 68 to close the fuel cock of themanually operable valve means I6 will open the switch I32 and rotationof the knob 68 to open the cock of the manually operable valve means I6will close the switch I32.

The-clockiactuated switch- .1 26'-'-I-28 and-. thea manually operableswitch l32-jareconnected in... series in the energizing circuit-of: the:solenoid; winding ofi-theisolenoidivalve I81 This energizin'g. circuit;is completed when both: switches are: closed and may be: traced asfollows line. wire L I, wire I '38l wirez I 40; solenoidwinding of'.sole- L noi'd valve- I 8 ,i'wire-: I342, wire I44; switch I32,';wireI4.6,'- cont'act 12K of thexclockactuated. mech'az- I nism: I22; switch:bl'ade I 24,and wire: al.48l-tottline WireaLL.

Ana: energizing circuit f-cr the igniter' 2c is cone necte'd in parallel:with the: solenoid winding of the; solenoid 'valve -I 8 and may 'betraced; as= fol:- lows: wire |3"8 l16 Oft. thei contactseIHlt f ctheswitching. device: IIM, movable plate I I2. ofthe: switching-device I063the othersof thev pair loficonetacts Ill); zofsthe switching device104-; wire I 59', lower-iterminali of theprimtry windingof a stepdown:transformer I52, upper. terminal of: the,

primary winding of the transformer I52, and. wire. I44: Thus, when thesolenoid. winding of the solenoid valve I8 is: energized-and. theswitching devi'cea I64 is:closed,.1currentswill flow through. theprimarywindin'g ofzthe transformer I521 Energization. of. the primary.windingof' the. transformer. I52 willtcausea current to= be induced inthe secondaryswinding. thereof and such.current will fiow through acircuit which may be tracedi as. follows: lower terminal of. thesecondary winding of thetransformer I52,.wire I54; ballast resistor.I56,.wire I58, igniter 20, wire I60, ballastiresistor I56 and wire I62to the upper terminalof. the secondary-winding of. the: transformer I52.1

It will be: apparent that the parallel circuit which includesth'eenergizing circuit for the sole-: noid winding of the solenoid valve I8and the energizing circuit for the igniter will be inter.- ruptedby theopenin of either the clock actuated switch I26UI28orthe manual switchI32. It will also. be apparent that the energizing circuit of the.igniter 2i]. will lee-interrupted by the opening of the thermallyresponsive switching device I04.

Operation Assuming that the apparatus is in the condition shown in thed'r'awinggwith no flame existing at any of the burners and it is desiredto adlust'the apparatus for automatic operation, the timer I32 is set tomove theplunger I to close the switch ZS-I28 at a selected time and theknob 68 is rotated to move the fuel cock of the manually 0perable valvemeans I6 to an open position; Such rotation of the-knob 68 willcause-the cam element I to engage theactuating lever I34 of the switchI32 to close the switch I32 so that when the timer I32'moves the switchblade I24 into engagement with the contact I28, the previously tracedenergizing circuit for the solenoid winding or" the solenoid valve I8 iscompleted and the solenoid valve I8 will assume itsfuel now permitting"position. Fuel will then flow from the supply conduit: I2 through theconduit BILsolenoid valve I8; conduittIZ, manually operablenvalve meansI6, and conduit 24 tothei pilot burner 22. I

Since the, bulb of the thermally-responsive actuating. meansis in itsunheated condition, the mechanismiinlthe casing, 26 will be in theposition shownimthe drawingwith the thermally responsive valve means .I4preventing flow of fuel to the main..burner II], the standby pilotvalve-88 preventingiflow of fuel'to. the standby pilot burner 65fCurrent;.fiowingathmuglrltheigniten 202 .wilrlai'seitstemperatureszrflicientlytczcanseignition.of the;- fuelflowing:fromrthel pilotz bumeri22ttu:producea flanrezdiizectediagainstthesbulb. fill".

Asatheatempetature citzthebuib Iifliaincreases, the

expansihle element: 56.:will" expand, causing an up-; ward movementraoiithe thrust :button; 64. and. counterclockwise rotation of the1ever.'5Il about;its pivot 52. .Asv hereinbefore. described,l.suchrotation of .the lever 50 will cause opening of thenor mally: closed.valve; means-IA; and. standby: .pilot switchingrdevicel. 1011:.outzofziengagement: with the contacts-1L0; J. I

TfilISfi1B1lWi1LfiQW frcmxhcimanually. operable. valvesmeans I Ethroughtheconduit 1:4, in-18110138111. ing;.30i= otwallve: means M-valve. chamber.28',. past. valve; seat; 3 5-,. thtonghithe. outlet:opening 32, of; thewalrze means I.4.-, and through conduit; to: the:mai'n:burner -10 where:-itt..will heignitedbv the;

flame at the pilot burner 22. Fuel will also. flow from; that supplyf.conduit. I2, through the conduit 8 6:. toxthea valve: chamber: BIL of:the: standbyrpilot i valve; 8.&' past-'ethei'valvexseat 36, through111185.011trr'.

letxopeningflfl .oitthe.:standbypilotvalve 8.8; and...

through the:- conduit. 8b. mthezstandby pilotburnermainibummxtulrlln...

When the plate; I 22: ofi-theswitching: device- .tflfi 'isrmovedcutof.engagement. with; thecontact. I1 (I,

the; energizing: circuitioiutheienitenlfl'. iszintere I rupted: :and:theiigniten-i II; will; be: deenergized.

control, Tot thethermostatically actuated {valve associatediwithmanually-operable valve means:

IS in accordance with the: temperaturesensed by;

the; temperature sensing element 76;".

Whenthe timer;3.2' of the clock actuated meche; anism I22 acts to movethe switch blade I24-out;

. of engagementwiththe contact. I28,j the energizingcircuitof.theqsolencid Winding of the solenoid.

valved-8' iszinternupted a-nd the solenoid winding is .deenergized-.xThe solenoid valve I8: will then act: to shutiofli alltheflow of. fuelfrom, the sup.-

. ply conduit Ii2v through the conduit 80;. Thus, the

fuelsupply to themainbumer I0 andto the pilot burner 22v will be 'cutoil and. the flames at said burnersrw-illlie-extinguished.

Uponvextinguishment; of the flame; at the pilot.

burner 22;.the; bulb '60 Will 0001' causing contrac tionaofztheexpansible element 56. and. clockwise.- rotationxof: the. levenil).about, its pivot 52' under theibiaa ofi the-springsy luand 4.: Ashereinbefore: set; .fortlr,=,:. such.: clocl wise:. rotation of; thelevenifl: wilhpermit thezvalvei member: 33. of the valve-means- I4:tozengage its;:seat..'3 63' and the valve member: 98. oft-he standbypilot. valve 88 will en gage: itszseatsfie Thus,.zthe-fuel Supply to thestandby pilotzburner. I12 will 'be cut off and the flame.thereatewillzbeextinguished. .l The apparatus isnowinthe conditionshown'in the drawing withrtuel: :sunnln toall burners prevented.

It. willab'ezapparent; fromlthev foregoing that the.ihereinrdisclosedrapparatus provides a. control system ronfluid fuel'burners wherein a single clock actuated swi'tch is effe'ctive tocontrol ad-' missionyignitionandcut-ofi of fuel thereby pro vi'dlh'g fora simple economical clock control and that it accordingly. accomplishes'the objects of the invention.

as aflameexlstsat thepi-lotzburnerx.

Although a specific embodiment of the invention has been shown anddescribed, it will be apparent that many modifications may be made bythose skilled in the art. Such modifications may be made in the detailsof construction and arrangement of parts without departing from thescope of the invention as set forth in the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a fluid fuel burner control system having main and pilot burners,ignition means for igniting fuel flowing from the pilot burner, valvemeans responsive to the presence of flame at the pilot burner forcontrolling the supply of fuel to the main burner, manually operablevalve means for controlling the supply of fuel to said last named meansand to the pilot burner, and timing means for controlling the supply offuel to said manually operable valve means at preselected intervals.

2. In a fluid fuel burner control system having main and pilot burners,means for igniting fuel flowing from the pilot burner, valve meansresponsive to the presence of flame at the pilot burner for controllingthe supply of fuel to the main burner, manually operable valve means forcontrolling the supply of fuel to said last named means and to the pilotburner, main valve means for controlling the supply of fuel to saidmanually operable valve means, electrically operable actuating means forsaid main valve means, an energizing circuit for said electricallyoperable actuating means, a switch in said energizing circuit, andtiming means for moving said switch between open and closed positions atpreselected intervals.

3. A control system as claimed in claim 2 wherein said energizingcircuit includes a switch operatively associated with said manuallyoperable valve means to be closed when said manually operable valvemeans is in fuel flow permitting position and open when said manuallyoperable valve means is in fuel flow preventing position.

4. In a fluid fuel burner control system having main and pilot burners,means for igniting fuel flowing from the pilot burner, means responsiveto the presence of flame at the pilot burner for controlling the supplyof fuel to said main burner,

condition responsive means for controlling the flow of fuel to said lastnamed means, manually operable valve means for controlling the flow offuel to said condition responsive means and to the pilot burner, mainvalve means for controlling the supply of fuel to said manually operablevalve means, electrically operable actuating means for said main valvemeans, an energizing circuit for said electrically operable actuatingmeans, a switch in said energizing circuit, and timing means for movingsaid switch between open and closed positions at preselected intervals.5. In a fluid fuel burner control system having main and pilot burners,means responsive to the presence of flame at the pilot burner forcontrolling the supply of fuel to the main burner, manually operablevalve means for controlling the supply of fuel to said last named meansand the pilot burner, an electric igniter for the pilot burner, mainvalve means for controlling the supply of fuel to said manually operablevalve means, electrically operable actuating means for said main valvemeans, and timing means for simultaneously energizing said electricigniter and said electrically operable actuating means.

6. A control system as claimed in claim 5 8 wherein thermally responsivemeans ar provided for deenergizing said electric igniter when a flame isestablished at the pilot burner.

7. In a fluid fuel burner control system having main and pilot burners,an electric igniter for the pilot burner, means responsive to thepresence of flame at the pilot burner for controlling the supply of fuelto the main burner, condition responsive valve means for controlling theflow of fuel to said last named means, manually operable valve means forcontrolling the flow of fuel to said condition responsive valve meansand to the pilot burner, main valve means for controlling the supply offuel to said manually operable valve means, electrically operableactuating means for said main valve means, an energizing circuit forsaid electric igniter and said electrically operable actuating means, aswitch in said energizing circuit, and timing means for moving saidswitch between open and closed positions.

8. A control system as claimed in claim '7 wherein said energizingcircuit includes a second switch operatively associated with saidmanually operable valve means to be moved between open and closedpositions thereby when said manually operable valve means is movedbetween fuel flow permitting position and fuel flow preventingpositions.

9. In a fluid fuel burner control system having main and pilot burnersand a source of electric power, a normally closed valve for controllingthe supply of fuel to the main burner, an electric igniter for the pilotburner, means responsive to the presence of flame at the pilot burnerfor opening said normally closed valve, manually operable valve meansfor controlling the supply of fuel to said normally closed valve and tothe pilot burner, valve means for controlling the supply of fuel to saidmanually operable valve means, electrically operable actuating means forsaid main valve means, connecting means between said electricallyoperable actuating means and said source, said connecting means includina clock actuated switch, an energizing circuit for said igniter, saidigniter energizing circuit being connected in parallel with saidelectrically operable actuating means, a switch in said igniterenergizing circuit, and means for operating said last named switch.

10. A control system as claimed in claim 9 wherein said last named meansis responsive to the presence of flame at the pilot burner.

ll. In a fluid fuel burner control system having main and pilot burnersand a source of electric power, a normally closed valve controlling thesupply of fuel to the main burner, an electric igniter for the pilotburner, manually operable valve means for controlling the supply of fuelto said normally closed valve and the pilot burner, main valve means forcontrolling the supply of fuel to said manually operable valve means,electrically operable actuating means for said main valve means,connecting mean betw en said electrically operable actuating means andsaid source, said connecting means includin a clock actuated switch anda second switch operatively associated with said manually operable valvemeans, an energizing circuit for said igniter, said igniter energizingcircuit being connected in parallel with said electrically operableactuating means, a switch in said igniter energizing circuit, and meansresponsive to the presence of flame at the pilot burner for opening saidnormally closed valve and said last named switch.

12. In a fluid fuel burner control system having 9 main and a pluralityof pilot burners, means for igniting fuel flowing from one ofthe pilotburners, means responsive to the presence of flame at said one pilotburner for controllingflthe supply of fuel to the main burner, manuallyoperable valve means for controlling the supply of fuel to said lastnamed means and said one pilot burner, means responsive to the presenceof flame at said one pilot burner for controlling-the supply of fuel toanother of the pilot burners,]main valve means for controlling thesupply of fuel to said manually operable valve means, electricallyoperable actuating means for said main valve means, an energizingcircuit for said electrically operable actuating means, a switch in saidenergizing circuit, and timing means for moving said" switch betweenopen and closed positions at preselected intervals;

13. In a fluid fuel burner control system having main and a plurality ofpilot burners, means responsive to the presence of flame at one of thepilot burners for controlling the supply of fuel to the main burner,means responsive to the presence of flame at said one pilot burner forcontrolling the supply of fuel to another of the pilot burners, manuallyoperable valve means for con- 25 ;fuel to another of the pilot trollingthe supply of fuel tosaid first named means and said one pilot burner,an electric igniter for said one pilot burner, main valve means forcontrolling the supply of fuel to said manually operable valve means,electrically operable actuating means for said main valve means, andtiming means for simultaneously energizing said electric igniter andsaid electrically operable actuating means.

, 14. In a fluid fuel burner control system having main anda pluralityof pilot burners and a source I of electric power, a normally closedvalve conally operable valve means for controlling the sup- .-pl y offuel to said normally closed valve and said fone pilot burner, mainvalve means for controlling the supply of fuel to said manually operablevalve means, electrically operable actuating means for "said main valvemeans, connecting means between said electrically operableactuatingmeans and said source, said connecting means includa clock actuatedswitch and a second switch .o peratively associated with said manuallyoperable valve means, an energizing circuit for said igniter, saidigniter energizing" circuit being connected in parallel with saidelectrically operable actuating means, a switch insaid igniter energiz-Qing circuit, means responsive to the presence of flame at said onepilot burnerfor opening said normally closed valve and said last namedswitch, and means responsive to the presence of flame at said one pilotburner for controlling the flow of burners. VICTOR WEBER.

REFERENCES CITED UNITED STATES PATENTS Name Date Meacham Sept. 22, 1936Number

